[Intel-gfx] [PATCH] drm/i915/vlv: Add VLV specific force wake routines.

[S, Deepak]

Hi Jesse,

Thanks for the review. Below is my response. 

>  - why not use the callback to __vlv_force_wake_* from
    gen6_gt_force_wake_*?  i.e. why is VLV special here?
[Deepak]   Gen6 has a single power well whereas the  VLV is has spate wells. This was the reason  for the separate function

 > - having a new gen7_media_force_wake function may be better than
    passing an engine around, and would touch fewer pieces of code
[Deepak]  Even Gen7  is also as single Power Well. Having common function between gen7 and vlv might be difficult to individually handle the wells.

  >- have you done measurements on this?  given how infrequently we
    ought to be waking the wells when they're idle, and how long we
    generally keep them awake, is this a real power win?
[Deepak] By Individually controlling the wells we observed around 100mW - 200mW  saving in different scenarios (GL Beanchmark & Media playback).

Thanks,
Deepak

-----Original Message-----
From: Jesse Barnes [mailto:jbarnes at virtuousgeek.org] 
Sent: Tuesday, November 19, 2013 11:36 PM
To: S, Deepak
Cc: intel-gfx at lists.freedesktop.org
Subject: Re: [Intel-gfx] [PATCH] drm/i915/vlv: Add VLV specific force wake routines.

On Thu, 14 Nov 2013 19:02:15 +0530
deepak.s at intel.com wrote:

> From: Deepak S <deepak.s at intel.com>
> 
> Added media/render/common well VLV force wake routines to help bring 
> up the WELLS before access the register
> - Refactor current vlv_forcewake get/put and added MEDIA or
>   RENDER specific Forcewake.
> - Added VLV Check to bring up MEDIA and RENDER WELL base
>   on the register accessed in vlv_read##x (in intel_uncore.c)

This patch is pretty big and so a bit hard to review.  A couple of
questions:
  - why not use the callback to __vlv_force_wake_* from
    gen6_gt_force_wake_*?  i.e. why is VLV special here?
  - having a new gen7_media_force_wake function may be better than
    passing an engine around, and would touch fewer pieces of code
  - have you done measurements on this?  given how infrequently we
    ought to be waking the wells when they're idle, and how long we
    generally keep them awake, is this a real power win?

Thanks,
Jesse